1. Field of the Invention
The present invention relates generally to a durable, multiple-use needle-free (or needle-less) hypodermic jet injection device, and to methods of its making, operation, and use. More particularly, this present invention relates to such a device and to such methods which provide both improved safety and ease of use for a user of the device, as well as providing both improved ease and economy of manufacture and improved durability for the device.
2. Related Technology
Needle-less or needle-free hypodermic jet injection devices have been in commercial use for over 40 years. A number of these devices have used pressurized gas to power a hypodermic jet injection. The related technology includes a number of teachings for gas-powered injection devices, including:
U.S. Pat. No. 4,596,556, issued Jun. 24, 1986 to J. Thomas Morrow, et al.;
U.S. Pat. No. 4,913,699; issued Apr. 3, 1990 to James S. Parsons; and
U.S. Pat. No. 5,730,723, issued Mar. 24, 1998, to Thomas P. Castellano, et al.
WIPO publication WO 97/37705 also discloses a gas powered disposable needle-less hypodermic jet injector.
Each of these devices has, limitations, deficiencies, or disadvantages, as will be apparent in view of the following detailed description of a single embodiment of the present invention
In view of the above, it is desirable and is an object for this invention to provide a needle-free jet injection device which reduces the severity of or avoids one or more of the limitations, deficiencies, or disadvantages of the conventional technology.
Particularly, it is an object for this invention to make a needle free injector which is safer to use because by its design, it cannot be activated or discharged to effect an xe2x80x9cinjection eventxe2x80x9d while a user of the device is installing or removing an injection cartridge of the device. Safety of use of the device is thus vastly improved.
Further, an object for this invention is to provide such a needle free injector in which certain component parts are so configured, constructed and arranged that they serve at least two functions, and in some cases, plural functions, in the operation and structure of the device.
Thus, it is an object of this invention to provide a durable, needle-free gas-powered hypodermic jet injector including a device body having provision for engaging with and carrying a jet injection cartridge; a gas piston reciprocable in the device body and cooperable with the jet injection cartridge to effect a jet injection in response to communication of pressurized gas to the gas piston; a valve device for effecting communication of pressurized gas to the gas piston in response to movement of the valve device from a first to a second position; and a safety ring rotationally carried on the device body and in a respective first position preventing movement of the valve device from the first to the second position, the safety ring being rotationally movable to a respective second position in which the valve device is movable from the first to the second position.
Further, this present invention provides an improved facility for a user to load and unload a pressurized gas capsule into and from the device.
Accordingly, an embodiment of the present invention provides a device body defining a cavity for receiving therein a pressurized gas capsule, the cavity being closed by a door member pivotally secured to the device body by a hinge pin, and the gas pressure cartridge being impaled at a penetrable diaphragm portion thereof upon a penetrator member of the injection device in response to closing of the door so that gas pressure within the gas pressure cartridge acting on the penetrator member causes a recoil force directed axially of the device; the hinge pin being disposed off axis of the device body so that the recoil force passes off center of the hinge pin in a direction relative to the hinge pin causing a closing torque to be effected on the door.
According to a further aspect this invention provides: a gas powered hypodermic jet injection device including a device body having a forward end; an axially extending recess at the forward end for receiving and retaining an injection cylinder which includes cylinder bore in which an injection piston is sealingly movable to cooperatively define a variable-volume chamber for holding a dose of liquid medication, and a fine-dimension orifice for forming the liquid medication into a high-velocity injection jet in response to forceful movement of the injection piston, the injection cylinder having a pair of diametrically opposite latching lugs projecting radially outwardly at an aft portion thereof; a gas pressure piston sealingly reciprocable in the device body, and forcefully moving the injection piston in the cylinder in response to communication of gas pressure to the gas pressure piston; a valve device for communicating pressurized gas from a source thereof to the gas pressure piston in response to axially forward relative movement of a trigger sleeve outwardly disposed on the device body; a multi-function safety ring rotationally carried on the device body and in a respective first position: a) preventing movement of the valve device from the first to the second position, the safety ring being rotationally movable to a respective second position in which the trigger sleeve of the valve device is movable from the first to the second position, and b) in the first position the safety ring allowing movement of the injection cartridge into and from the recess, in the second rotational position the safety ring both preventing movement into and out of the recess of the injection cartridge; and c) in the first position the safety ring allowing a latching member to move laterally to allow axial insertion of an injection cartridge manually into the recess, and so as to latch with the injection cartridge at the latching lugs thereof, in the second rotational position, the safety ring preventing the latching member from moving laterally so as to prevent unlatching of the latching member from the latching lugs of an injection cartridge disposed in the recess.
Additional objects and advantages of this invention will appear from a reading of the following detailed description of two exemplary preferred embodiments of the invention, taken in conjunction with the appended drawing Figures, in which the same reference numeral is used throughout the several views to indicate the same feature, or features which are analogous in structure or function.